Facebook is celebrating another milestone as its Messenger app hits one billion monthly active users. That's 60% of Facebook's 1.65 billion monthly users and makes it one of only a handful of apps worldwide to cross the 1 billion user mark. WhatsApp, which Facebook bought for a jaw-dropping $19 billion, hit the milestone in February while the main Facebook app already counts upwards of 1.5 billion monthly active users.

The company made Messenger a standalone app in 2014, unbundling it from the main Facebook client to offer a more focused and feature rich experience. The move annoyed many as it essentially forced to download another app, but nonetheless Messenger's popularity soared to 500 million users by the end of that same year.

Even before the unbundling Facebook had big plans for the service, dropping the requirement have a Facebook account in order to use Messenger.

TechCrunch has a post detailing the app's path to one billion including some impressive facts: As many as 17 billion photos are sent each month, 380 million stickers and 22 million GIFs are sent each day and 10% of all VoIP calls go through Messenger. The bot platform Facebook introduced for Messenger at F8 has grown to include over 18,000 bots